Open hole expandable packer with extended reach feature

Abstract

An open hole packer uses mandrel expansion and a surrounding sealing element that can optionally have a swelling feature and further a seal enhancing feature of a ring with an internal taper to match an undercut on the mandrel exterior. As a swage progresses to the taper at the transition between the ring and the extending flat fingers, the fingers get plastically deformed in an outward radial direction to push out the sealing element. Shrinkage of the mandrel axially due to radial expansion brings a ring on the mandrel outer surface under the fingers to act as a support for the fingers against the seal which is pushed against the open hole. Mirror image orientations are envisioned to aid in retaining pressure differentials in opposed directions. Another external mandrel ring extends into the seal to keep its position during differential pressure loading.

We claim: 
     
       1. A packer for subterranean use in a borehole extending from a surface location and defined by a borehole wall, comprising:
 a tubular housing defining a housing wall surrounding a passage therethrough, said housing wall having an outer surface and an inside surface in contact with fluids flowing between the subterranean location and the surface; 
 a sealing element surrounding said outer surface; 
 at least one sealing boost force device on said outer surface of said housing wall and further comprising at least one cantilevered member supported, for a time, only at one end thereof when acting on said sealing element between said sealing element and said outer surface of said housing wall by relative radial movement of a free end thereof that, for a time, is not supported, said relative radial movement occurring with respect to a radial movement of said outer surface as said passage is expanded to urge said sealing element toward the borehole wall which, for a time, separates said free end from support from said outer surface of said housing wall. 
 
     
     
       2. The packer of  claim 1 , wherein:
 said cantilevered member urged against said sealing element by expansion of said housing. 
 
     
     
       3. The packer of  claim 1 , wherein:
 said sealing boost force device is located at least in part in an undercut formed on an outer surface of said housing. 
 
     
     
       4. The packer of  claim 3 , wherein:
 a portion of said sealing boost force device is not covered by sealing element and said portion extends radially, before said housing is expanded, at least as far as said sealing element. 
 
     
     
       5. The packer of  claim 3 , wherein:
 said sealing element extends in part into said undercut before said housing is expanded. 
 
     
     
       6. The packer of  claim 3 , wherein:
 said undercut is eliminated with expansion of said housing. 
 
     
     
       7. The packer of  claim 1 , wherein:
 said sealing element is secured to said housing only to a location spaced apart from said cantilevered member. 
 
     
     
       8. The packer of  claim 1 , wherein:
 said housing further comprises at least one retaining member extending into said sealing member to axially fixate said sealing member to said housing. 
 
     
     
       9. The packer of  claim 1 , wherein:
 said at least one sealing boost force device comprises opposed sealing boost force devices disposed in mirror image to each other. 
 
     
     
       10. The packer of  claim 1 , wherein:
 said at least one sealing boost force device comprises a plurality of sealing boost force devices disposed in alignment with each other. 
 
     
     
       11. The packer of  claim 1 , wherein:
 said cantilevered member comprises a plurality of cantilevered fingers extending generally axially from a ring mounted around said housing. 
 
     
     
       12. The packer of  claim 11 , wherein:
 said fingers defining axially oriented gaps between them; 
 said fingers have overlapping free ends to close said gaps. 
 
     
     
       13. The packer of  claim 1 , wherein:
 said sealing element having an end adjacent a free end of said cantilevered member. 
 
     
     
       14. The packer of  claim 13 , wherein:
 said sealing element at least wholly covers said sealing boost force device. 
 
     
     
       15. The packer of  claim 13 , wherein:
 expansion of said housing bends said cantilevered member away from said housing to move said sealing element against the borehole wall while leaving a gap for pressurized borehole fluids to get between said housing and said cantilevered member to boost the sealing force against the borehole wall. 
 
     
     
       16. A packer for subterranean use in a borehole extending from a surface location and defined by a borehole wall, comprising:
 a tubular housing defining a housing wall surrounding a passage therethrough, said housing wall having an outer surface and an inside surface in contact with fluids flowing between the subterranean location and the surface; 
 a sealing element surrounding said outer surface; 
 at least one sealing boost force device on said outer surface of said housing wall and further comprising at least one cantilevered member supported, for a time, only at one end thereof when acting on said sealing element between said sealing element and said outer surface of said housing wall by relative radial movement of a free end thereof that, for a time, is not supported, said relative radial movement occurring with respect to a radial movement of said outer surface as said passage is expanded to urge said sealing element toward the borehole wall which, for a time, separates said free end from support from said outer surface of said housing wall; 
 said housing further comprises a support member that moves toward said cantilevered member as a result of longitudinal shrinkage of said housing from radial expansion thereof. 
 
     
     
       17. The packer of  claim 16 , wherein:
 said cantilevered member comprises a plurality of cantilevered fingers extending generally axially from a ring mounted around said housing. 
 
     
     
       18. The packer of  claim 17 , wherein:
 said fingers defining axially oriented gaps between them; 
 said fingers have overlapping free ends to close said gaps. 
 
     
     
       19. The packer of  claim 1 , wherein:
 said ring is axially restrained by said housing. 
 
     
     
       20. The packer of  claim 16 , wherein:
 said sealing element is secured to said housing only to a location spaced apart from said support member. 
 
     
     
       21. The packer of  claim 20 , wherein:
 an end of said sealing member that is not secured to said housing is pushed toward the borehole wall by said sealing boost force device and said sealing boost force device permits pressurized borehole fluid to get between said housing and said sealing element to enhance the boost from said sealing boost force device against the wall. 
 
     
     
       22. A packer for subterranean use in a borehole extending from a surface location and defined by a borehole wall, comprising:
 a tubular housing defining a housing wall surrounding a passage therethrough, said housing wall having an outer surface and an inside surface in contact with fluids flowing between the subterranean location and the surface; 
 a sealing element surrounding said outer surface; 
 at least one sealing boost force device on said outer surface of said wall and further comprising at least one cantilevered member acting on said sealing element between said sealing element and said outer surface of said wall by radial movement of a free end thereof with respect to a radial movement of said outer surface as said passage is expanded to urge said sealing element toward the borehole wall; 
 said housing further comprises a support member that moves toward said cantilevered member as a result of longitudinal shrinkage of said housing from radial expansion thereof; 
 said cantilevered member comprises a plurality of cantilevered fingers extending generally axially from a ring mounted around said housing; 
 said fingers connected to said ring through a tapered transition such that expansion of said housing engages said transition to force said fingers to plastically rotate about said transition and toward said sealing element. 
 
     
     
       23. The packer of  claim 22 , wherein:
 said tapered transition is located adjacent an end of an undercut formed on an outer surface of said housing. 
 
     
     
       24. A packer for subterranean use in a borehole extending from a surface location and defined by a borehole wall, comprising:
 a tubular housing defining a housing wall surrounding a passage therethrough, said housing wall having an outer surface and an inside surface in contact with fluids flowing between the subterranean location and the surface; 
 a sealing element surrounding said outer surface; 
 at least one sealing boost force device on said outer surface of said wall and further comprising at least one cantilevered member acting on said sealing element between said sealing element and said outer surface of said wall by radial movement of a free end thereof with respect to a radial movement of said outer surface as said passage is expanded to urge said sealing element toward the borehole wall; 
 said housing further comprises a support member that moves toward said cantilevered member as a result of longitudinal shrinkage of said housing from radial expansion thereof; 
 said cantilevered member comprises a plurality of cantilevered fingers extending generally axially from a ring mounted around said housing; 
 said support member located between said housing and said sealing element and movable from an initial location at a spaced axial distance from a free end of said fingers to a second location between said free end of said fingers and said ring. 
 
     
     
       25. The packer of  claim 24 , wherein:
 said support member comprises at least one continuous ring or spaced segments on said outer surface of said housing. 
 
     
     
       26. A packer for subterranean use in a borehole extending from a surface location and defined by a borehole wall, comprising:
 a tubular housing defining a housing wall surrounding a passage therethrough, said housing wall having an outer surface and an inside surface in contact with fluids flowing between the subterranean location and the surface; 
 a sealing element surrounding said outer surface; 
 at least one sealing boost force device on said outer surface of said wall and further comprising at least one cantilevered member acting on said sealing element between said sealing element and said outer surface of said wall by radial movement of a free end thereof with respect to a radial movement of said outer surface as said passage is expanded to urge said sealing element toward the borehole wall; 
 said cantilevered member comprises a plurality of cantilevered fingers extending generally axially from a ring mounted around said housing; 
 said fingers connected to said ring through a tapered transition such that expansion of said housing engages said transition to force said fingers to plastically rotate about said transition and toward said sealing element. 
 
     
     
       27. The packer of  claim 26 , wherein:
 said tapered transition is located adjacent an end of an undercut formed on an outer surface of said housing. 
 
     
     
       28. The packer of  claim 26 , wherein:
 said fingers plastically rotate with or without expansion of said ring. 
 
     
     
       29. A packer for subterranean use in a borehole extending from a surface location and defined by a borehole wall, comprising:
 a tubular housing defining a housing wall surrounding a passage therethrough, said housing wall having an outer surface and an inside surface in contact with fluids flowing between the subterranean location and the surface; 
 a sealing element surrounding said outer surface; 
 at least one sealing boost force device on said outer surface of said wall and further comprising at least one cantilevered member acting on said sealing element between said sealing element and said outer surface of said wall by radial movement of a free end thereof with respect to a radial movement of said outer surface as said passage is expanded to urge said sealing element toward the borehole wall; 
 said cantilevered member comprises a plurality of cantilevered fingers extending generally axially from a ring mounted around said housing; 
 a support member located between said housing and said sealing element and movable from an initial location at a spaced axial distance from a free end of said fingers to a second location between said free end of said fingers and said ring.